The present invention relates to the field of firearms and more particularly, to highly precise examples of such apparatus as used in competitive target shooting, wherein every variable factor influencing accuracy must be consistently maintained on successive shots.
Competitive target shooting is pursued at many levels, from that of an Olympic event to a recreational pastime. Serious competitors take great pains in their selection and fine tuning of equipment. Ballistic experimentation with different combinations of bullet weights, powder types and charges, together with painstaking preparation and hand loading of cartridges is a given. While the human aspects of maintaining an accurate point-of-aim, including compensation for cross-winds, are basic differentiating factors in scoring, other factors affect the accuracy with which a round strikes at the point-of-aim. It is the reduction of variation in these other factors that is essential to approaching the unattainable, xe2x80x9cperfect marksmanshipxe2x80x9d. In the case of a rifle, bedding of the barrel and receiver in the stock may be critical to accuracy. Dynamic characteristics of the barrel, that is, tube vibrations induced by discharge, may also be critical. In short, any physical effect that can vary, ever so slightly, from one round to the next, will affect the point-of-aim accuracy achieved by a given rifle. Skilled marksmen know it is desirable to maintain a uniform barrel temperature for every group of shots, because barrel temperature variations, especially uneven barrel heating or cooling, will degrade accuracy. Thus, at the highest levels of competition, skilled marksmen prefer to sight their rifle in hot, fire several warm-up groups before shooting for score, and hope for cooling periods between firing sequences to hold fairly uniform barrel temperatures. Barrel temperature control may be quite difficult under match conditions, especially while trying to avoid uneven cooling.
Military requirements are more severe. Here accuracy is not the issue so much as barrel life. Rapid fire sequences, without adequate cooling periods, will overheat the barrel so much that the rifling grooves are washed out and the barrel is ruined. In military service, it is a common practice to carry a spare barrel as a back-up, or as an exchange to allow cooling periods.
Therefore, a first object of the present inventions is to provide method and apparatus for enhancing the rate of barrel cooling. A second object of the present inventions is to provide method and apparatus for uniform barrel cooling at this enhanced rate. A third object is to provide method and apparatus that can be implemented under actual field conditions. Another object of the present inventions is to provide readily usable apparatus for extending barrel life under field conditions. Yet another object is to achieve these results at a reasonable cost to the end user, while still allowing a profit incentive for commercial production and distribution.
The present inventions contemplate improved methods and apparatus for gun barrel cooling. These inventions relate to or employ some steps and apparatus well known in the arts and therefore, not the subject of detailed discussion herein. The present inventions comprise improved methods and apparatus for cooling the barrel of a gun providing that the gun has a receiver configured to receive a magazine.
In a preferred embodiment of the present inventions the shell of a magazine for a given firearm, normally holding a plurality of rounds, is gutted to provide an appropriate housing. As an alternative, a similar part can be formed in sheet metal or plastic. A small, DC fan, of the type commonly used for circulation of cooling air through the interior of electronic devices and of a size suitable for mounting within the transverse inside dimensions of the housing, provides air flow for cooling. The mounting location of the fan is such that its air outlet will be directed into the chamber of the firearm when the housing is installed in the manner of a magazine. A DC power supply, preferably included inside of the housing, in the form of one or more batteries and a circuit connector/disconnector, completes this embodiment of the present inventions. The circuit connector/disconnector may be located where it is automatically operated by insertion of the barrel cooler housing into the receiver, or it may be located where it is accessible for manual operation. A useful accessory, for firearms having a bolt that does not lock in a retracted position on an empty chamber, is a bolt stop plate at the rear of the housing. Another useful accessory is an indicator flag, which extends from the ejector port when the barrel cooler is inserted, making it obvious that the weapon is in a safe condition.